West Australians remain in the dark about looming COVID-19 restrictions as the highly infectious Omicron variant spreads in the community.
Face masks are again being enforced in Perth and the Peel region after 18 new local cases were reported in the past week, including three on Monday.
From 6pm on Monday, masks must also be worn in the South-West region.
Multiple cases have been linked to U Natural Spa Therapy in the riverside suburb of Applecross, including four people who worked there.
At least one of those staff also worked at a massage parlour in Mt Lawley while infectious, prompting an urgent call for anyone with COVID-19 symptoms to get tested.
"We expect there are more cases in the community and we need to track them down," Premier Mark McGowan told reporters.
"Test results that are returned today and tomorrow will be telling."
The government has outlined stringent new proof of vaccination requirements that will come into effect ahead of the February 5 border reopening.
But the premier on Monday again declined to reveal what public health restrictions would apply to people who are vaccinated or how the government would define close contacts of COVID-19 cases.
Mr McGowan is also yet to release any modelling on the likely impact of the Omicron variant.
The Australian Medical Association believes WA could face up to 60,000 cases per day unless tough rules are enforced.
It says South Australia was headed for a peak of 30,000 to 40,000 daily infections before re-introducing limits on private and public gatherings.
The state is now anticipating between 6000 and 10,000 cases.
AMA WA president Mark Duncan-Smith said given WA's higher population, it could face a daily peak of between 50,000 and 60,000 new Omicron cases in March or April unless similar rules are introduced.
"If we introduce restrictions early and adequately, that will reduce to approximately 10,000 new cases per day at that peak," he told reporters.
"WA's medical system needs to be protected. It doesn't have the capacity to deal with COVID without reducing business as usual."
Curtin University epidemiologist Archie Clements said West Australians could expect strict restrictions given the premier's cautious approach throughout the pandemic.
He said individuals were also likely to take their own precautions as WA emerged from almost two years with no major outbreaks.
"I do think that we'll be seeing tens of thousands of cases in around March-April. I think that's probably where we're heading," he told AAP.
"WA hasn't had a big outbreak yet so people are very nervous. We've lived in blissful isolation, I suppose, but people have seen what's happened elsewhere and they are really concerned, so I do think people will exercise a lot of caution."
Dozens of exposure sites have been listed in recent days, spreading across Perth and the Swan Valley and as far south as Margaret River.
Perth Festival meanwhile announced it would no longer proceed with its multi-venue opening event which had been scheduled for February 11 and 12.
The festival cited difficulties with proof of vaccination requirements and the availability of staff and artists due to potential illness or isolation.
Australian Associated Press